Progress in Microfluidic Nuclear Magnetic Resonance
Nuclear magnetic resonance (NMR) has matured into an extremely powerful technique, with applications ranging from chemical analysis to molecular biology to medical diagnostic imaging. Unfortunately, the hardware associated with this technique has traditionally been large, immobile, expensive, and required frequent specialized maintenance. Microfluidic technology has allowed for a great reduction in complexity and expense for most common analytical techniques; however, little work has been done to leverage the advantages of microfluidics and nuclear magnetic resonance in a single device. In this thesis, I describe advances toward the goal of creating small, portable, inexpensive, easy-to-use NMR microfluidic instrumentation. First, I describe projects relating to the use of Xe-129 chemical sensors on microfluidic devices. I demonstrate a silicon and glass microdevice which allows the production and optical detection of hyperpolarized Xe-129 at low magnetic fields. The device enhances the NMR sensitivity of Xe-129 experiments by a factor 10^4 on hardware that is a factor of 10^6 smaller in size and power requirements than current polarizers. I describe techniques for patterning arrays of Xe-129 chemical sensors on microfluidic devices and using them to detect chemicals at picomolar sensitivities. These technologies may be integrated to produce highly integrated portable devices for detecting arbitrary chemicals in complex fluids. Due to the use of NMR as the detection modality, they may be used on dirty samples which cannot be interrogated through the use of optical spectroscopy or mass spectrometry, such as biofuels or whole human blood. The second part of this thesis deals with a method of encoding imaging information using arrays of thin magnetic films instead of magnetic field gradients. This technique obviates the need for large instrumentation in imaging experiments and may allow for greater portability, further increasing the practicality of microfluidic NMR experiments. These advances represent a significant step toward microscale NMR technology.